Oil-fired, infrared heater

ABSTRACT

An oil-fired infrared heater is disclosed including a conical, thin wall combustion chamber of high temperature refractory fiber removably disposed within and supported at its opposite ends by a cylindrical sheet metal housing. One end of the housing supports an oil burner assembly by which oil and air are introduced into one end of the combustion chamber, and an apertured metal plate is disposed across the opposite end of the chamber and is removably interconnected with the cylindrical housing. The apertures in the metal plate account for a very small percentage of the total area thereof, whereby a considerable amount of inner and outer metal surface area exists about and between the plate apertures. During burner operation the chamber wall and the apertured plate are heated to incandescence. The apertures in the plate allow products of combustion to escape outwardly of the combustion chamber, and the inner and outer surface portions of the plate respectively reflect heat back into the chamber and radiate heat outwardly from the outer surface of the apertured plate.

United States Patent 1 Mendelson 1 Oct. 2, 1973 1 OIL-FIRED, INFRARED HEATER [76] Inventor: Ralph R. Mendelson, c/o The Glass Lined Water Heater Co., 13000 Athens Ave., Cleveland Hts., Ohio 44107 [22] Filed: Mar. 8, 1972 [21] Appl. No.: 232,845

Primary Examiner-William E. Wayner Assistant Examiner-William E. Tapolcai, Jr. Attorney-James l-l. Tilberry et al.

[57] ABSTRACT An oil-fired infrared heater is disclosed including a conical, thin wall combustion chamber of high temperature refractory fiber removably disposed within and supported at its opposite ends by a cylindrical sheet metal housing. One end of the housing supports an oil burner assembly by which oil and air are introduced into one end of the combustion chamber, and an apertured metal plate is disposed across the opposite end of the chamber and is removably interconnected with the cylindrical housing. The apertures in the metal plate account for a very small percentage of the total area thereof, whereby a considerable amount of inner and outer metal surface area exists about and between the plate apertures. During burner operation the chamber wall and the apertured plate are heated to incandescence. The apertures in the plate allow products of combustion to escape outwardly of the combustion chamber, and the inner and outer surface portions of the plate respectively reflect heat back into the chamber and radiate heat outwardly from the outer surface of the apertured plate.

10 Claims, 4 Drawing Figures o 0 000 /OOOQOGO 0 00 00 00 00 0 0 0 0 0 0 000 0 00 00 0 000000000000000 0 0000000 00000000 oooooooooooooooooo 00 00 00 00000 0 00 0000 00 0 00 0 00 0 0 0 0 0 0 00 SHEET 2 BF 3 IO l4 0 000000 0000000 00000000 oooooo 000000000000000000 0000000000000 0000 0 000000000 0 0 000000000 090 o o o 0 00000000 OIL-FIRED, INFRARED HEATER The present invention relates to the art of infrared generators and more particularly, to a fuel-fired infrared generator.

Infrared heaters or generators have been provided heretofore for the purpose of radiating heat to an object in the path of the output thereof without wasting heat on the air between the generator and the object to be heated. Such infrared generators are ideal for use in buildings or outdoor areas where frequent air temperature changes occur. The heating of objects in areas of the latter character by other heating devices becomes extremely inefficient and ineffective due to the heating of the air between the heater and the object.

Several factors affect the desirability and acceptance of infrared generators of the foregoing character. For example, if a considerable number of such generators are required to perform a desired heating function within a building or outdoors, it becomes desirable for the units to be relatively inexpensive, readily and adjustably mountable or positionable relative to the object or objects to be heated, inexpensive to maintain and efficient in operation both from the standpoint of cost of operation and radiating efficiency. Further, with regard to fuel-fired infrared generators, it becomes desirable that combustion and burning of the fuel-air mixture in the combustion chamber of the device be as complete as possible to reduce the exhaust of contaminates therefrom during operation thereof.

The present invention advantageously provides a liquid fuel-fired infrared generator having the foregoing desirable characteristics. In this respect, the generator is comprised of a minimum of component part which are of light-weight construction and which are structurally interrelated in a manner whereby assembly and disassembly thereof is achieved in a minimum amount of time and with a minimum of physical effort, all of which lends to a unit which is relatively inexpensive to produce and maintain and which, because of the lightweight construction thereof, is readily portable, and is easy to handle or manipulate during installation thereof.

In accordance with another aspect of the present invention, the structure of the generator provides for greater fuel burning and heat radiating efficiencies than heretofore possible. In this respect, the generator includes a combustion chamber adapted to receive a fuel-air mixture through one end thereof for burning therein, and an apertured end wall which extends across the other end of the combustion chamber. The apertured wall has an inner and outer surface relative to the combustion chamber, each of which surfaces is divided into generally planar surface portions disposed between or around the apertures through the wall. The generally planar surface portions have a surface area many times greater than the area of an aperture through the wall. During operation of the generator, the combustion chamber and end wall are heated to incandescence, and the inner surface portions of the end wall reflect heat inwardly of the combustion chamber to assure a more complete burning of the fuel within the chamber than heretofore possible. The outer surface portions of the end wall radiate heat outwardly from the end wall. Preferably, the total area of the apertures through the end wall is between 1 to percent of the total surface area of one of the inner and outer wall surfaces. It will be appreciated, therefore, that considerable surface area is available for reflecting heat inwardly of a combustion chamber and radiating heat outwardly of the wall, whereby fuel burning and heat radiating efficiencies are increased.

An object of the present invention is the provision of a fuel-fired infrared generator which is inexpensive to produce and maintain.

Another object is the provision of an infrared generator of the foregoing character comprised of a minimum number of parts structurally interrelated to provide for assembly and disassembly thereof in a minimum amount of time and with minimum effort.

A further object of the present invention is the provision of an infrared generator of the foregoing character having structural characteristics providing for the unit to be, selectively, portable or permanently installed and to be adjustable relative to the support therefor.

Yet another object of the present invention is the provision of a fuel-air fired infrared generator including a combustion chamber and an apertured wall associated therewith and having inner and outer surface portions for respectively radiating heat outwardly of the chamber and reflecting heat inwardly of the chamber.

Still another object of the present invention is the provision of a liquid fuel-fired infrared generator in which a more complete burning of the fuel in the combustion chamber is achieved than heretofore possible.

Yet another object of the present invention is the provision of an infrared generator of the foregoing character wherein the radiation of heat outwardly of the chamber is greater than heretofore possible.

The foregoing objects, and others, will in part be obvious and in part more fully pointed out hereinafter in conjunction with the description of the drawing in which:

FIG. 1 is an exploded perspective view of the components of a preferred structure of an infrared generator made in accordance with the present invention;

FIG. 2 is a side elevation view of the assembled generator illustrating the generator mounted on a stand;

FIG. 3 is a plan view, in section, of the generator illustrated in FIG. 2, the view being taken along line 33 in FIG. 2; and

FIG. 4 is a plan view of the apertured end wall component of the generator.

Referring now to the drawing in greater detail wherein the showings are for the purpose of illustrating a preferred embodiment of the invention only and not for the purpose of limiting the same, an infrared generator unit 10 is illustrated which is comprisedof a combustion chamber component 12, a cylindrical sheet metal housing member 14, housing end wall components 16 and 18, and a fuel burner unit 20.

Combustion chamber component 12 may be produced from any suitable high temperature refractory material and may have any desired structural configuration which will provide for an inner chamber surface which converges from the outer end thereof toward the inner end of the chamber. In the embodiment illustrated the combustion chamber component is of thin walled generally conical construction and has an inner surface 22 which converges generally uniformly from outer end 22a thereof toward the inner end of the chamber. The inner end of the chamber component is defined by a curved wall portion 24 having an opening 26 therethrough and an integral cylindrical sleeve 28 extending rearwardly from the opening for the purpose set forth more fully hereinafter. Preferably, combustion chamber component 12 is produced from a high temperature refractory fiber material having an organic or ceramic bonding agent therein and which is molded or otherwise shaped to provide a generally conical, thin wall chamber component in which the wall thickness is substantially uniform throughout. A suitable material from which the combustion chamber component can be fabricated is marketed by Johns-Manville Company of Manville, NJ under the trademark CERA-FORM. The latter material is extremely lightweight and heats to incandescence upon burning of a fuel-air mixture in the combustion chamber. While surface portion 22 of the combustion chamber preferably converges generally uniformly from the outer end thereof toward the inner end of the chamber, it will be appreciated that the inner surface of the chamber wall could be otherwise configured and could, for example, have an arcuate or curved contour in longitudinal cross section.

Cylindrical housing component 14 is of thin gauge sheet metal such as aluminized steel and is of substantially uniform diameter between the opposite ends thereof. Preferably, component 14 is constructed by forming a tube from a sheet metal blank and interconnecting the free ends of the blank by suitable fastener elements 30. It will be appreciated, however, that the housing component could be otherwise constructed. Housing component 14 is of a longitudinal length corresponding substantially to the longitudinal length of combustion chamber component 12, and is closed at one end thereof by end wall 18. Wall 18 is a sheet metal component of aluminized steel or the like, and is provided with a longitudinally extending peripheral flange 32 adapted to axially receive the corresponding end of housing component 14. Suitable fastener elements such as screws 34 serve to removably interconnect end wall 18 with the housing component.

Wall 18 is provided substantially centrally thereof with a cylindrical opening 36 which is surrounded by a cylindrical metallic sleeve element 38 which projects longitudinally inwardly of housing component 14 from wall 18. Sleeve 38 may be integral with end wall 18 or may be a separate component suitably attached thereto. Further, sleeve 38 has an outer diameter corresponding substantially to the inner diameter of cylindrical sleeve portion 28 of combustion chamber component 12. This relationship provides for sleeve 38 to slidably receive and support the inner end of the combustion chamber component relative to wall 18 and housing component 14. The outer end of the combustion chamber component slidably engages and is supported by the corresponding end of housing component 14 which has an inner diameter, at least at the outer end 140 thereof, which corresponds substantially to the outer diameter of outer end 120 of the combustion chamber. lt will be appreciated that this structural relationship provides for the combustion chamber components to be readily introduced into and removed from the housing as defined by housing component 14 and end wall 18 and to be supported laterally within the housing without the use of fastener elements or the like.

Wall 18 also serves to support fuel-air burner unit which, in the embodiment illustrated, includes a fuel nozzle 40 and an air nozzle portion 42 disposed within sleeve 38 and adjacent the inner end of the combustion chamber. The air nozzle portion includes an end plate 44 having a central opening aligned with the fuel nozzle and surrounded by a plurality of vanes 46 which direct air in a swirling pattern into the combustion chamber to mix with and swirl the fuel in a circular path relative to the longitudinal axis of the combustion chamber. In

the illustrated embodiment, the fuel is oil and is delivered to nozzle by a pump component 48 of the fuelair burner assembly 20. Pump 48 receives fuel from a suitable source, not illustrated through line 49. Air is delivered through the air nozzle toward the combustion chamber by a fan component 50 of the burner assembly 20, and fan 50 and pump 48 are driven by electric motor 52 of assembly 20 through motor shaft means 53. Electrodes 57 are disposed adjacent the outlet end of nozzle 40 to provide for ignition of the fuel-air mixture for burning in the combustion chamber, and it will be appreciated that the electrodes are connected to a suitable source of electrical power not illustrated. Further, it will be appreciated that suitable controls can be provided as a part of the fuel air assembly to control operation of the various components thereof in response to the detection or failure to detect establishment of a flame in the combustion chamber. Fuel-air burner unit 20 may be provided with any suitable support structure to facilitate removably mounting the assembly as a unit on end wall 18. For example, a support plate 54 may be attached to the burner unit housing 55 in any suitable manner and removably interconnected with end wall 18 such as by nut and bolt assemblies 56. Preferably, spacers 58 are interposed between plate 54 and wall 18 to reduce heat transfer therebetween which might be detrimental to certain of the components of the fuel-air assembly 20.

End wall 16 extends across the outer end of combustion chamber component 12 and is provided with a multiplicity of apertures 60 extending therethrough. In the preferred embodiment, end wall 16 is a thin, cylindrical plate of No. 22 gauge stainless steel having a longitudinally extending peripheral flange 62 adapted to axially receive the corresponding end of housing component 14. Suitable fastener elements such as screws 64 provide for end wall 16 to be removably interconnected with housing component 14. When end wall 16 and end wall 18 are interconnected with housing component 14, it will be appreciated that these components cooperate to restrain any significant longitudinal movement of the combustion chamber component 12 relative to housing component 14. It will be appreciated, of course, that either or both of the end walls 16 and 18 could be interconnected with housing component 14 by means other than the flange and fastener arrangement illustrated. For example, housing component 14 could be provided at one or both of its end with radially outwardly or inwardly projecting peripheral flanges to which the end walls could be secured.

Openings 60 preferably are cylindrical and of uniform diameter and are generally uniformly spaced apart across end wall 16. The total area of the openings 60 is extremely small relative to the total surface area of each of the inner and outer surfaces of end wall 16. In this respect, the total area of the openings is between from 1 to 5 percent of the total surface area of either the inner or outer surface of the end wall within marginal edge 60a thereof. Within this range, a total area of the openings of from about 1 percent to about 4 percent has been found most desirable. It will be appreciated, therefore, that a surface area of from about to 99 percent of the total surface area of the end wall plate is exposed to define reflecting and radiating surface portions respectively on the inner and outer surfaces of the end wall. It will be further noted, that the individual surface portions disposed between or surrounding the openings are generally planar surfaces, the total area of which is available for reflecting or radiating functions to be described more fully hereinafter.

Openings 60 may be provided in end wall 16 randomly or in a suitable pattern and, preferably, are provided in the pattern illustrated in FIG. 4. In this respect, a plurality of openings 60 are provided in each of a plurality of radially spaced apart coaxial annular paths 66. The circumferential spacing between adjacent openings 60 in all of the paths 66-is substantially equal, and the radial spacing between annular paths 66 is generally uniform. It will be appreciated that this pattern provides for more openings to be provided in one path 66 than in a radially inwardly adjacent path 66. This particular pattern provides for the individual surface portions of the end wall lying between a circumferentially adjacent pair of openings and an opening radially adjacent one of the circumferentially adjacent pair to be of generally equal area to one another throughout the total surface of the wall. Surface portions defined in the foregoing manner are designated by numerals 68 in FIG. 4, and it will be appreciated that these areas exist on both the inner and outer surfaces of the end wall. Such areas could, of course, be otherwise defined and the use of a triangular grouping of the openings is intended merely to demonstrate that the inner and outer surfaces include surface portions between the openings which are generally planar surfaces. The preferred pattern arrangement advantageously provides for each of the exposed surface portions to have generally the same reflecting and radiating capacity, and for the end wall as a unit to have generally uniform reflecting and radiating characteristics across the surfaces thereof. It will be appreciated that the pattern could be varied so that the surface portions would not be of uniform area and that the desirable feature that the surface portions are generally planar would not be lost.

It will be noted that the inner surface of wall 16 is slightly concave. This configuration is preferred in that it prevents the wall from flexing and making an objectionable popping sound upon heating. Although the wall is slightly arcuate in cross section, it will be appreciated that the inner and outer surface portions thereof are generally planar surfaces. In this respect, in the embodiment illustrated wall 16 is approximately 22 inches in diameter and the center thereof is axially displaced about one inch with respect to peripheral edge 16a.

As a specific example of a generator made in accordance with the present invention, the apertured end wall is produced from No. 22 gauge stainless steel which is 0.031 inch thick. The wall is approximately 22 inches in diameter. Approximately 1,260 cylindrical openings three thirty-seconds inch in diameter are provided in the wall in the pattern described above. In this respect the openings are provided in annular paths of 1 inch to inches in diameter, which paths are radially spaced apart one-half inch. Six holes are provided in the first path and 120 in the outermost path. The number of holes increases by six progressively from the inner to the outer path. Thus, the inner and outer surfaces of the wall each have a total area of approximately 380 square inches, and the total area of the openings relative to each surface is approximately 8.69 square inches, or 2.29 percent of the total area. Thus, approximately 97.7 percent of each of the inner and outer surface areas are available for heat reflection and heat radiation. Further, the unit has a longitudinal dimension including the burner unit of 26 k inches, and a housing length of 18 inches. The unit is liquid fuel fired, burns approximately 1.0 gallons per hour, and the burner unit is operable with fuel oil, kerosene, diesel fuel or jet engine fuel, and has an input capacity of 140,000 btu per hour. The weight of the unit including a mounting stand or bracket of the character described herein, is approximately 64 pounds. In operation, with oil as the fuel, a flame temperature of about 2,500 F exists inside the chamber. Preferably the pressure in the combustion chamber is maintained between about 0.04 to 0.14 inches H O. Further, the temperature of the apertured end wall during operation of the generator under these conditions is about l,550 F.

When a fuel-air mixture is introduced into and ignited to burn in combustion chamber component 12, the combustion chamber component and wall 16 are heated to incandescence. Openings provide for products of combustion to escape from the combustion chamber and forwardly thereof. Heat is radiated toward wall 16 from surface 22 of the combustion chamber component and is reflected back into the combustion chamber toward the inner end thereof by the inner surface portions 68 of wall 16. Reflection of heat in this manner, together with the establishment of a pressure within the chamber resulting from the small outlet area defined by openings 60, serves to provide far more complete combustion than would otherwise be possible. In this respect, the liquid fuel is dispensed through nozzle 40 as an oil spray and the reflected heat serves to further vaporize the liquid fuel to assure a more complete burning thereof. The increase in the amount of fuel burned which is achieved in accordance with the present invention advantageously provides a reduction in pollutants exhausted from the generator during use thereof, better fuel economy, and increased radiating efficiency. Still further, the chamber pressure resulting from the extremely small area defined by openings 60, together with the heat reflecting capability of the inner surface portions of the wall, advantageously provide for the fuel-air mixture to burn in the combustion chamber in an area spaced inwardly from wall 16, whereby there is no burning of the fuel-air mixture at the wall 16 to cause a flame forwardly thereof. Burning of the fuel-air mixture completely within the combustion chamber advantageously provides for reducing the exhaust of contaminates or pollutants from the generator which would result if the fuel were burned at the wall. While the exact location of the forward end of the burning area within the chamber can not be readily determined, it is believed from visual observation of operation of the generator illustrated that such burning generally takes place in the area inwardly of line A in FIG. 3. When the unit is shut down, it is advantageous to provide for the air blower to'continue to operate for a pe riod of time so that the heat in the combustion chamber area will not adversely affect the liquid fuel in the fuel nozzle. More particularly, such continued air circulation maintains the nozzle at a temperature below that which might cause the fuel to become gummy and clog the fuel nozzle passageway. It will be appreciated that suitable control means can be provided for this pur- I pose. Further, it will be appreciated that the generator unit could have a configuration other than the cylindrical configuration illustrated and could, for example, be square in transverse cross section.

The generally planar outer surface portions of wall 16 provide a large total surface area for radiating heat forwardly of the generator. ln this respect, it will be appreciated that in the preferred embodiment from 95 to 99 percent of the total area of the outer surface of wall 16 is available for radiating heat, thus to provide the unit with extremely high heat radiating efficiency.

As described hereinabove, housing component 14 preferably is cylindrical and of uniform diameter. This provides for an air space 72 between the combustion chamber component and housing component to act as a barrier against heat transfer to the housing component. The effectiveness of the air space will be appreciated when it is considered that when the skin temperature of the housing component adjacent outer end 14a thereof is about 600 F during operation of the generator the skin temperature of the housing component adjacent the opposite end thereof is about 400 F. Heat transfer to the housing member could, of course, be further reduced by providing insulating material in the air space.

It will be appreciated in view of the foregoing description of the preferred embodiment that an infrared generator is provided which can be readily constructed from inexpensive materials and which is comprised of a minimum of components which are structurally interrelated in a manner to facilitate assembly and disassembly thereof. Thus, the unit can be readily assembled initially and can thereafter be readily disassembled for purposes of cleaning or replacing components, or performing other maintenance operations with respect thereto. Further, the light-weight construction of the unit facilitates handling thereof during installation or during transfer thereof from one location of use to another. In this respect, the unit can be installed in a fixed position'relative to support means therefor such as a ceiling in a building, or the unit can be mounted for ground or floor support. For this purpose, a stand and- /or bracket assembly such as that indicated by numeral 74 in FIG. 2 of the drawing can be employed. With regard to the latter support arrangement, assembly 74 may be defined by suitable angle iron leg and brace components, and the infrared generating unit can be adjustably mounted thereon by means of wing nut-type fasteners 76 which interconnect the stand-bracket assembly and housing component 14 and/or end wall 18 in a manner permitting pivotal adjustment of the unit relative to the assembly. It will be appreciated, of course, that assembly 74 could be provided with wheels or the like to further facilitate movement of the unit from one location to another when it is ground or floor supported.

While considerable emphasis has been placed therein on the fact that apertured wall 16 of the unit is a stainless steel sheet metal component, it will be appreciated that the end wall could be produced from other sheet metal materials or from materials other than sheet metal such as refractory materials.

As many possible embodiments of the present invention may be made and as many possible changes may be made in the embodiment herein described, it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the present invention and not as a limitation.

I claim:

1. An infrared generator comprising: a combustion chamber of refractory material and having opposite ends, means at one end of said chamber for introducing fuel and air into said chamber for burning therein, and an apertured metal plate across the other end of said chamber, said metal plate having inner and outer generally planar surface portions between the apertures therein, said combustion chamber and metal plate being heated to incandescence upon burning of a fuelair mixture in said chamber, the apertures in said metal plate allowing products of combustion to escape outwardly of said chamber, and said inner and outer generally planar surface portions of said metal plate respectively reflecting heat back into said chamber toward said one end thereof and radiating heat outwardly of said other end of said chamber, said metal plate being stainless steel and said apertures defining an open area therethrough of about from 1 to 5 percent of the total area of a surface thereof.

2. An infrared generator comprising: a combustion chamber of refractory material and having opposite ends, means at one end of said chamber for introducing fuel and air into said chamber for burning therein, and an apertured metal plate across the other end of said chamber, said metal plate having inner and outer generally planar surface portions between the apertures therein, said combustion chamber and metal plate being heated to incandescence upon buring ofa fuel-air mixture in said chamber, the apertures in said metal plate allowing products of combustion to escape outwardly of said chamber, and said inner and outer generally planar surface portions of said metal plate respectively reflecting heat back into said chamber toward said one end thereof and radiating heat outwardly of said other end of said chamber, the fuel-air mixture burned in said combustion chamber including a liquid fuel vapor, said inner surface portions of said metal plate reflecting heat back toward said means for introducing a fuel-air mixture into said chamber to further vaporize said liquid fuel and promote burning of said fuel-air mixture in said chamber and inwardly of said metal plate, said apertures in said metal plate defining an open area therethrough of about 1 to 5 percent of the total area of a surface thereof.

3. A liquid fuel-fired infrared generator comprising: a refractory combustion chamber component open at the opposite ends thereof and having a conical wall of generally uniform thickness between said opposite ends thereof, nozzle means at the smaller diameter end of said wall for introducing liquid fuel and air into the combustion chamber for burning therein, an apertured metal plate across the larger diameter end of said wall having inner and outer surface portions between the apertures therein, said component and said metal plate being heated to incandescence upon burning of a fuelair mixture in said chamber component, said inner surface portions reflecting heat back into said chamber component for said fuel-air mixture to burn therein behind said plate, said outer surface portions radiating heat outwardly with respect to said chamber component, and housing means for said combustion chamber component, including a housing component having opposite ends and an end wall at one end of said housing component, said combustion chamber component being removably supported in said housing means with the smaller diameter open end thereof adjacent said end wall, said end wall having sleeve means projecting toward the other end of said housing component for receiving said smaller diameter end of said combustion chamber component to support the latter end, and said housing component including a wall portion engaging and supporting said wall of the combustion chamber component forwardly of said end wall.

4. The infrared generator according to claim 3, wherein said sleeve means opens into said combustion chamber component and said nozzle means is disposed in said sleeve means.

5. The infrared generator according to claim 4, wherein said housing component is cylindrical and has an inner diameter corresponding generally to the outside diameter of the larger diameter end of said wall of said combustion chamber component, said housing component extending from said end wall a distance sufficient for said latter end of said wall of said combustion chamber component to be disposed inside said housing component.

6. The infrared generator according to claim 5, wherein said apertured metal plate is removably attached to said housing component.

7. A liquid fuel-fired infrared generator comprising: a refractory combustion chamber component open at the opposite ends thereof and having aconical wall of generally uniform thickness between said opposite ends thereof, nozzle means at the smaller diameter end of said wall for introducing liquid fuel and air into the combustion chamber for burning therein, an apertured metal plate across the larger diameter end of said wall having inner and outer surface portions between the apertures therein, said component and said metal plate being heated to incandescence upon burning of a fuelair mixture in said chamber component, said inner surface portions reflecting heat back into said chamber component for said fuel-air mixture to burn therein behind said plate, said outer surface portions radiating heat outwardly with respect to said chamber component, and said inner and outer surface portions each having a surface area of about 95 to 99 percent of the total area of the corresponding surface of said metal plate.

8. The infrared generator according to claim 6, wherein said inner and outer surface portions each total a surface area of about to 99 percent of the total area of the corresponding surface of said metal plate.

9. A liquid fuel-fired infrared generator comprising: a refractory combustion chamber component open at the opposite ends thereof and having a conical wall of generally uniform thickness between said opposite ends thereof, nozzle means at the smaller diameter end of said wall for introducing liquid fuel and air into the combustion chamber for burning therein, an apertured plate across the larger diameter end of said wall having inner and outer surface portions between the apertures therein, said component and said plate being heated to incandescence upon burning of a fuel-air mixture in said chamber component, said inner surface portions reflecting heat back into said chamber component for said fuel-air mixture to burn therein behind said plate, and said outer surface portions radiating heat outwardly with respect to said chamber component, and housing means for said combustion chamber component, including a housing component having opposite ends and an end wall at one end of said housing component, said combustion chamber component being removably supported in said housing means with the smaller diameter open end thereof adjacent said end wall, said end wall having sleeve means projecting toward the other end of said housing component for receiving said smaller diameter end of said combustion chamber component to support the latter end, and said housing component including a wall portion engaging and supporting said wall of the combustion chamber component forwardly of said end wall.

10. The infrared generator according to claim 9, wherein said housing component is cylindrical and has an inner diameter corresponding generally to the outside diameter of the larger diameter end of said wall of said combustion chamber component, said housing component extending from said end wall a distance sufficient for said latter end of said wall of said combustion chamber component to be disposed inside said housing component. 

1. An infrared generator comprising: a combustion chamber of refractory material and having opposite ends, means at one end of said chamber for introducing fuel and air into said chamber for burning therein, and an apertured metal plate across the other end of said chamber, said metal plate having inner and outer generally planar surface portions between the apertures therein, said combustion chamber and metal plate being heated to incandescence upon burning of a fuel-air mixture in said chamber, the apertures in said metal plate allowing products of combustion to escape outwardly of said chamber, and said inner and outer generally planar surface portions of said metal plate respectively reflecting heat back into said chamber toward said one end thereof and radiating heat outwardly of said other end of said chamber, said metal plate being stainless steel and said apertures defining an open area therethrough of about from 1 to 5 percent of the total area of a surface thereof.
 2. An infrared generator comprising: a combustion chamber of refractory material and having opposite ends, means at one end of said chamber for introducing fuel and air into said chamber for burning therein, and an apertured metal plate across the other end of said chamber, said metal plate having inner and outer generally planar surface portions between the apertures therein, said combustion chamBer and metal plate being heated to incandescence upon buring of a fuel-air mixture in said chamber, the apertures in said metal plate allowing products of combustion to escape outwardly of said chamber, and said inner and outer generally planar surface portions of said metal plate respectively reflecting heat back into said chamber toward said one end thereof and radiating heat outwardly of said other end of said chamber, the fuel-air mixture burned in said combustion chamber including a liquid fuel vapor, said inner surface portions of said metal plate reflecting heat back toward said means for introducing a fuel-air mixture into said chamber to further vaporize said liquid fuel and promote burning of said fuel-air mixture in said chamber and inwardly of said metal plate, said apertures in said metal plate defining an open area therethrough of about 1 to 5 percent of the total area of a surface thereof.
 3. A liquid fuel-fired infrared generator comprising: a refractory combustion chamber component open at the opposite ends thereof and having a conical wall of generally uniform thickness between said opposite ends thereof, nozzle means at the smaller diameter end of said wall for introducing liquid fuel and air into the combustion chamber for burning therein, an apertured metal plate across the larger diameter end of said wall having inner and outer surface portions between the apertures therein, said component and said metal plate being heated to incandescence upon burning of a fuel-air mixture in said chamber component, said inner surface portions reflecting heat back into said chamber component for said fuel-air mixture to burn therein behind said plate, said outer surface portions radiating heat outwardly with respect to said chamber component, and housing means for said combustion chamber component, including a housing component having opposite ends and an end wall at one end of said housing component, said combustion chamber component being removably supported in said housing means with the smaller diameter open end thereof adjacent said end wall, said end wall having sleeve means projecting toward the other end of said housing component for receiving said smaller diameter end of said combustion chamber component to support the latter end, and said housing component including a wall portion engaging and supporting said wall of the combustion chamber component forwardly of said end wall.
 4. The infrared generator according to claim 3, wherein said sleeve means opens into said combustion chamber component and said nozzle means is disposed in said sleeve means.
 5. The infrared generator according to claim 4, wherein said housing component is cylindrical and has an inner diameter corresponding generally to the outside diameter of the larger diameter end of said wall of said combustion chamber component, said housing component extending from said end wall a distance sufficient for said latter end of said wall of said combustion chamber component to be disposed inside said housing component.
 6. The infrared generator according to claim 5, wherein said apertured metal plate is removably attached to said housing component.
 7. A liquid fuel-fired infrared generator comprising: a refractory combustion chamber component open at the opposite ends thereof and having a conical wall of generally uniform thickness between said opposite ends thereof, nozzle means at the smaller diameter end of said wall for introducing liquid fuel and air into the combustion chamber for burning therein, an apertured metal plate across the larger diameter end of said wall having inner and outer surface portions between the apertures therein, said component and said metal plate being heated to incandescence upon burning of a fuel-air mixture in said chamber component, said inner surface portions reflecting heat back into said chamber component for said fuel-air mixture to burn therein behind said plate, said outer surface portions radiating heat outwardly with respect to said chamber component, and said inner and outer surface portions each having a surface area of about 95 to 99 percent of the total area of the corresponding surface of said metal plate.
 8. The infrared generator according to claim 6, wherein said inner and outer surface portions each total a surface area of about 95 to 99 percent of the total area of the corresponding surface of said metal plate.
 9. A liquid fuel-fired infrared generator comprising: a refractory combustion chamber component open at the opposite ends thereof and having a conical wall of generally uniform thickness between said opposite ends thereof, nozzle means at the smaller diameter end of said wall for introducing liquid fuel and air into the combustion chamber for burning therein, an apertured plate across the larger diameter end of said wall having inner and outer surface portions between the apertures therein, said component and said plate being heated to incandescence upon burning of a fuel-air mixture in said chamber component, said inner surface portions reflecting heat back into said chamber component for said fuel-air mixture to burn therein behind said plate, and said outer surface portions radiating heat outwardly with respect to said chamber component, and housing means for said combustion chamber component, including a housing component having opposite ends and an end wall at one end of said housing component, said combustion chamber component being removably supported in said housing means with the smaller diameter open end thereof adjacent said end wall, said end wall having sleeve means projecting toward the other end of said housing component for receiving said smaller diameter end of said combustion chamber component to support the latter end, and said housing component including a wall portion engaging and supporting said wall of the combustion chamber component forwardly of said end wall.
 10. The infrared generator according to claim 9, wherein said housing component is cylindrical and has an inner diameter corresponding generally to the outside diameter of the larger diameter end of said wall of said combustion chamber component, said housing component extending from said end wall a distance sufficient for said latter end of said wall of said combustion chamber component to be disposed inside said housing component. 